Your carburetor is a Holley 2300 model. It was used on some IH light duty vehicles with a V-345 and automatic transmission from 1970-72. Your carburetor was manufactured during the third week of October, 1970, possibly making it the original carb that came on your IH. The original Holley master rebuild kit for it was 85R-3502-S, although this is likely an obsolete number by now. The Napa Echlin equivalent kit is CRB 25529, although this kit may not have a Holley manufactured power valve and needle and seat assembly. I would recommend rebuilding your carburetor. Hope that helps you!

Is there somewhere else on this site (Holley) which has the specs for these (his 6206, and my 4574) models?

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I am not aware of a detailed source of information about Holley OEM carburetors, such as your 4574 that is online, unfortunately. The only places I could find such info for my List #4313 was in Holley Illustrated Parts & Specs, which is a 440 page technical manual in my possession, as well as the IH service manual.

Months ago, I did call Holley and the technicians there didn't have any correct information about my unit; the information they had was wrong and said my unit was governed! plus they didn't have the correct power valve specs. I did get it from the Daytona people, who have been making their own parts and rebuilding carburetors for long before Holley was sold/reorganized. I've gotten mixed results from a local Carburetor shop; their records seem to be either incomplete, or some employees don't know where to look for some of it.

As I understand it, Holley discarded much of the original books and other data about earlier products, concentrating on racing and performance equipment.

BTW, my unit (List 4574) is listed in my IH manual; it lists jets and such but doesn't have details about values for both stages of the two-stage power valves and nobody cross-references those IH part numbers, (which I do have).

Had the same problem with My Wagoneer, There are very few OEM carbs listed by holley on their site. There are other sources to find applications, The IH factory manuals are exellent on jets but the CFM was not considerd a need to know item by any OEM manufacturer. There was a book, How to rebuild Your'e Holley, publisher may have been petersen or hot rod with a very good listing of carbs up to the early seventys. This book also has many tuning secrets such as how to idle with a big cam. This book is essential reading if You want to really dial in a carb. Unfortunatly I never owned it but My old boss had a copy.

Months ago, I did call Holley and the technicians there didn't have any correct information about my unit; the information they had was wrong and said my unit was governed! plus they didn't have the correct power valve specs. I did get it from the Daytona people, who have been making their own parts and rebuilding carburetors for long before Holley was sold/reorganized. I've gotten mixed results from a local Carburetor shop; their records seem to be either incomplete, or some employees don't know where to look for some of it.

As I understand it, Holley discarded much of the original books and other data about earlier products, concentrating on racing and performance equipment.

BTW, my unit (List 4574) is listed in my IH manual; it lists jets and such but doesn't have details about values for both stages of the two-stage power valves and nobody cross-references those IH part numbers, (which I do have).

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Looked up your List 4574 Holley and the original Holley part number for your two stage power valve was 25R-475A-13. Thinking that the first stage of this power valve opens at 13 inches of Hg.(Mercury) and the second stage opens at approximately 6 inches of Hg.

Spring is here and I'm back working on the Holley mentioned at the start of this post (Model 2300). I've got the truck running much better after a rebuild kit was secured but I need to find a replacement fuel bowl for this carb as the threads are near junk (and have been repaired previously) for the accelerator pump assembly. Does anyone know what part number I should be looking for or can steer me in the right direction? I purchased one on ebay that I "thought" was going to work, but the fuel inlet was different and could not be modified to work.